The turbo is kinda small for the KA and you would have to have a turbo manifold custom made for the Mitsubishi turbo charger.
Those have side mount intercoolers, right? You probally could use it and toss it behind one of the fenders, but I don't think I have heard of anyone using a side mount intercooler on a 240, I may be mistaken on that.
Best bet is to rebuild the GST. If you want a Turbo 240 sell the DSM and start fresh. Or just keep the Mitsu and build it.